Final answer:
c) nematode parasitism evolved multiple times in each type of host (plants, verts, inverts)
In nematodes, parasitism evolved multiple times across different host types, including plants, vertebrates, and invertebrates.
Step-by-step explanation:
The evolution of parasitism in nematodes is complex and diverse. Based on the information provided, it is apparent that nematode parasitism has shown a multitude of evolutionary paths.
Nematodes, or roundworms, exhibit a wide range of parasitic lifestyles, some of which can have significant health impacts on their hosts, including humans, plants, and other animals. Parasitic nematodes have evolved mechanisms that enable them to infect and live off their hosts, and this has occurred multiple times across different host species.
Parasitism has manifested in many forms in these organisms, with certain species known to be internal parasites in humans and others that affect animals or thrive as plant parasites. The various strategies and adaptations nematodes have developed for parasitism imply that parasitism evolved multiple times, rather than having a singular evolutionary origin.
Therefore, the answer to the question is (c) nematode parasitism evolved multiple times in each type of host (plants, vertebrates, invertebrates).